The study proposes to evaluate various ways in which the hypertensive response to NaCl may be modified. These will include surgical, hormonal, dietary and stress modifications of the treatment of rats and other animals on a high salt intake. Blood pressure, organ weights, blood and urinary electrolyte changes, hematology and pathologic changes in organs and tissues will be used as criteria to be evaluated. It is hoped that the findings will permit comparisons with the changes in certain forms of human disease and thereby provide experimental models useful in studying systemic manifestations of clinical disorders.